Side wall separator fluidic logic device

ABSTRACT

A low power side wall separation fluidic logic device is disclosed having laminar flow characteristics. The device defines an element having a smooth, continuous, and gradual transition from a power jet throat to receiver output lines with a minimized angle being maintained between the receiver lines so as to achieve low power operation.

United States Patent 1191 Trask,II

14 1 Feb. 6, 1973 [54] SIDE WALL SEPARATOR FLUIDIC LOGIC DEVICE [75] Inventor: Roland Pierce Trask, [1, Silver Spring, Md.

[73] Assignee: The United States of America as represented by the Secretary of the Army [22] Filed. July 7, 1971 [2]] Appl. No.: 160,286

[52] U.S. Cl. ..l37/839 [51] Int. Cl, ..F15c l/08, Fl5d 1/06 [58] Field of Search .137/839 [56] References Cited U NITED STATES PATENTS Dexter 137/8 l .5

3,568,701 3/1971 Mon ..137/8l.5

3,378,023 4/1968 Beeken ..137 s1.5 3,550,607 12/1970 Sarpkaya ..l37/81.5

Primary ExaminerWilliam R. Cline AttorneyHarry M. Saragovitz et a].

[57] ABSTRACT A low power side wall separation fluidic logic device is disclosed having laminar flow characteristics. The device defines an element having a smooth, continuous, and gradual transition from a power jet throat to receiver output lines with a minimized angle being maintained between the receiver lines so as to achieve low power operation.

5 Claims, 2 Drawing Figures mmmrwelm 3.714.955

v m'srrrca ROLAND mince TRASK, 1':

IIATTOPNQYSH SIDE WALL SEPARATOR FLUIDIC LOGIC DEVICE The invention described herein may be manufactured, used, and licensed by or for the United States Government for governmental purposes without the payment to me of any royalty thereon.

BACKGROUND OF THE INVENTION This invention relates to fluidic devices and particularly concerns an improved construction of a side wall separation device so as to primarily exhibit laminar flow characteristics and thus enable low power operation, but transition and turbulent flow regions are also possible.

Conventionally constructed prior art fluidic logic devices, such as flip-flops, exhibit a number of disadvantages rendering such devices somewhat unsuitable for low power operation. Such conventional devices normally comprise a power jet inlet port, an interaction chamber, and a plurality of outlet receiver lines all of rectangular cross-section and constant aspect ratio as is known. Yet, with the conventional construction, these conventional devices incorporate setback side walls within the interaction chamber at the power jet nozzle exit. During operation of the prior devices, the power jet completely separates from the power nozzle and reattaches to one or the other of the sidewalls of the interaction chamber so as to provide a fluidic output signal at one or the other of the output ports provided. A basic and inherent requirement for such prior art devices concerns the fact that the power jet must be maintained in a turbulent state causing strong entrainment such that sufficient pressure gradients exist across the power jet at the separation regions within the interaction chamber to cause the jet to reattach to one or the other of the offset sidewalls.

To obtain this turbulent flow at the required locations within the interaction chamber, prior art devices of the type above-described required a relatively high power jet pressure and relatively high flow velocities.

SUMMARY OF THE INVENTION It is a primary object of the instant invention to provide a fluidic logic device that is capable of multi-stage operation and memory at very low input power levels.

It is a further object of the instant invention to provide a fluidic logic device which may exhibit laminar flow characteristics throughout its operation;

It is yet another object of the instant invention to provide a fluidic logic device which, at low power levels and with laminar flow, can exhibit a number of different logic functions.

These objects as well as others which will become apparent as the description proceeds, are implemented by the instant invention which, in a preferred embodiment thereof, will be seen to define a lowpower side wall separation fluidic logic device having geometry constraining laminar flow characteristics. The device is contemplated to include an input channel means which issues a laminar fluidic power stream from a throat thereof into a chamber, the chamber emptying into a plurality of output receiver channels. The geometry of the chamber is such that a smooth, continuous, and gradual transtion from the throat of the input channel means to the output receiver channels is effected. During operation, a laminar flow of the power stream is effected along both of two oppositely disposed and divergent side walls of the chamber to a separation region or point disposed downstream of the input channel means.

An adverse pressure gradient is effected at such separation point to thereby detach the power stream from one of the side walls whereby the power stream exits into the output receiver channel adjacent to the oppositely disposed side wall.

From a structural point of view, the preferred embodiment of the instant invention is such that the two side walls of the chamber diverge from one another along a radius of curvature of at least 20 times the width of the throat of the input channel means. Thus, the interconnection between the throat of the input channel means and the receiver lines is maintained at a gradual divergence. Furthermore, and in the preferred inventive embodiment, such gradual divergence is additionally maintained by disposing the output receiver channel means at an angle defined by the tangent to the side walls at or near the point where the receiver is located. Thus the angle between the receivers should be in the order of 40.

Control over the specific output state of the fluidic logic device of the instant invention can be achieved through the provision of control ports communicating with the chamber downstream of the power jet separation point above-described. In the preferred structural embodiment, the control ports are disposed substantially adjacent the output channel means. In this fashion, any geometrical discontinuities which are necessary to secure desired operation, such as the provision of control ports and/or vent passages if desired, occure downstream of the point within the chamber where the laminar power jet separates from a side wall.

By appropriate modifications in the geometry such as by canting the power jet nozzle so as to geometrically bias the power jet, the novel device of the instant invention can be utilized as an OR/NOR gate or a Schmidt trigger. Furthermore, by utilizing the side wall separation of the power jet with properly disposed control ports, the instant invention can operate as an AND/NAND gate or other single and multi-state low .power fluidic logic devices.

BRIEFv DESCRIPTION OF THE FIGURES The invention itself will be better understood and further advantageous features and structural characteristics thereof will become apparent from the following detailed description of a preferred inventive embodiment, such description referring to the appended sheet of drawings wherein:

FIG. I is a schematic illustration of a bi-stable fluidic logic device exhibiting conventional, prior art geometrical construction; and

FIG. 2 is a schematic illustration of the geometry of the instant invention providing a fluidic logic device in which laminar flow characteristics is' insured and in which low power operation can be achieved.

DETAILED DESCRIPTION OF A PREFERRED INVENTIVE EMBODIMENT Attention is initially directed to FIG. 1 of the appended drawings wherein a conventional and typical prior art fluidic logic device is depicted, this device exhibiting a multi-state operation. In the usual fashion, an input power jet nozzle is provided having a throat l2 communicating with an interaction chamber 14, the interaction chamber, in turn, communicating with two divergent receiver lines 16 and 18. The interaction chamber 14 incorporates two oppositely disposed side walls typically being setback a distance x from the throat 12 of the power jet input channel means 10. Control ports 24 and 26 communicate with the interaction chamber 14 adjacent to the throat 12 of the input channel 10 in the region of the setback side walls. On the whole, the internal geometry of such a conventional device is discontinuous and does not provide a smooth or gradual transition between the input channel means 10 and the various receiver lines 16 and 18.

Such discontinuous internal construction is necessary for the typical prior art device considering its usual mode of operation. Specifically, a power jet schematically illustrated at 28 existing the throat 12 of the input channel 10 completely separates from the power nozzle at the region of geometric discontinuity and then subsequently reattaches to one or the other of the interaction chamber side walls, such as at attachment point 30 along side wall 22, so as to exit via receiver line 18 providing fluidic output signal thereon. An inherent requirement for such a device to operate comprises the fact that the power jet 28 must be maintained in a turbulent state causing strong entrainment so that sufficient pressure gradients exist across the jet at the separation regions adjacent the throat 12 so as to cause the power jet to reattach to one of the offset side walls. As discussed at the outset to this specification, turbulent flow of the power jet 28 requires relatively high pressures and relatively great flow velocities, thus rendering a conventional device such as shown in FIG. 1 largely unsuitable for low power operation.

As opposed to the prior art construction of FIG. 1, the novel fluidic device of the instant invention depicted in FIG. 2 of the appended sheet of drawings exhibits no geometrical discontinuities near the power jet exit nozzle such as the setback side walls and the control ports of the prior art. Instead, the instant invention is physically characterized by the provision of gradually curved side walls and lack of geometrical discontinuities in the specific manner to be discussed hereinbelow.

The fluidic logic device of the instant invention incorporates the same or similar basic components as prior art logic devices such as an input channel means 32, a diffuser-type chamber 34, and output receiver channel means such as at 36, and 38, respectively. The chamber 34 itself will be seen to have two opposite and divergent side walls40 and 42 communicating between the throat 44 of the input channel means 32 and the output receiver channel means 36 and 38. The two divergent side walls 40 and 42 effect a smooth, continuous, and gradual transition from the throat of the input channel means to the output receiver channel means in a fashion whereby laminar flow of the power jet sche matically depicted as at 46 is insured.

During operation of the novel inventive device, the chamber means 34 and particularly the smooth, continuous, and gradual outward divergence of the side walls 40 and 42 thereof, effect a laminar flow of the power stream 46 along both of the side walls 40 and 42 as illustrated, to a downstream separation point or region 48. At this downstream separation point or region, the chamber geometry effects an adverse pressure gradient serving to thereby detach the power stream from one of the side walls, side wall 40 in the illustrated example, so that the power stream 46 exits into one or the other of the output receiver channels such as channel 38. By providing this preferred geometry, a laminar power jet which separates at only one point within the novel device is effected and this laminar flow characteristic enables the novel device to operate at substantially lower power levels than the turbulent devices of the prior art.

As above-stated, the criteria for the side wall construction of the chamber 34 is that such side walls effect a smooth, continuous, and gradual transition fromthe throat of the input channel means to the output receiver channel means. For purposes of insuring low power operation, the preferred inventive embodiment contemplates to make all of the geometric wall features as gradual as possible. in this respect, and assuming the width of the throat 44 of the input channel means 32 to be designated as W, it has been found that preferred operation can be assured when the aspect ratio is of a typical value, if the side walls 40 and 42 of the chamber means 34 diverge from one another along a radius of curvature of at least 20W. Additionally, and so as to further insure a gradual transition as above-described, the angle (1 between the outlet receiver channels or lines 36 and 38 is contemplated to be about equal to or less than 40. The choice of unusual aspect ratios might alter the aforementioned geometrical dimensions.

The instant invention contemplates the provision of control port means such as at 50 and 52 which communicate with the chamber 34 downstream of the laminar jet separation point 48, these control port means serving to switch the power stream 46 to exit into one or the other preselected output channel means 36 and 38, respectively. The control port means 50 and 52 thus, in this instance, would comprise the only discontinuities within the fluidic device but at a point downstream of the separation region 48. If such discontinuities were placed along the side walls 40 and 42 of the chamber 34 upstream of the separation point 48, premature separation of the power jet 46 from both side walls 40 and 42 mightbe triggered to thereby divert the power stream from the preselected or appropriate output. In the preferred inventive embodiment, the control port means 50 and 52 are disposed substantially adjacent the respective output channel means 36 and 38.

The above discussion of the preferred inventive embodiment generally described a multi-stable fluidic logic device constructed in accordance with the novel principles herein expressed. Yet, and as will be apparent, the power jet nozzle or input channel means 32 could be canted so as to geometrically bias the power jet 46 to one or the other of the side walls 40 and 42, respectively. In this manner, the fluidic logic device of the instant invention would operate as an OR/NOR gate, or a Schmitt trigger. Furthermore, and as-will be apparent, by utilizing the side wall separation characteristics of the fluid power stream 46 along with suitable geometry and placement of control port means, the novel fluidic device of the instant invention would be made to operate as an AND/NAND gate, or other single and multi-state low power logic device.

It should be understood, therefore, that the instant invention is not limited to the exact details of construction shown and described herein, for other obvious modifications will occur to persons skilled in the art. As should now be apparent, the objects set forth at the outset to this specification have been successfully achieved. Accordingly,

What I claim is:

l. A low power side wall separation fluidic logic device with laminar flow characteristics, said device comprising:

input channel means for issuing a laminar fluidic power stream from a throat thereof; output receiver channel means for receiving at least a portion of the power stream flow; and

a diffuser-type chamber having two opposite divergent side walls effecting a smooth, continuous, and gradual transition from the throat of said input channel means to said output receiver channel means, said chamber defining means for effecting laminar flow of the power stream along both of said side walls to a downstream separation point, control port means communicating with said chamber downstream of said separation point, said chamber thereat effecting an adverse pressure gradient to thereby detach the power stream from oneof said side walls whereby the power stream exits into the output receiver channel which is adjacent to the opposite side wall.

2. A device as defined in claim 1, wherein said control port means are disposed substantially adjacent said output channel means.

3. A device as defined in claim 1, wherein said throat of said input channel means has a width W, and wherein said side walls of said chamber diverge along a radius ofcurvature of at least 20W.

4. A device as defined in claim 1, wherein two output receiver channel meansare provided, said output receiver channel means diverging from one another at an angle of up to 40.

5. A device as defined in claim 1, wherein said control port means are disposed substantially adjacent said output channel means and wherein two output receiver channel means are provided, said output receiver channel means diverging from one another at an angle of up to 40, said throat of said input channel means defining a width W, and wherein said side walls of said chamber diverge along a radius of curvature of at least 20W. 

1. A low power side wall separation fluidic logic device with laminar flow characteristics, said device comprising: input channel means for issuing a laminar fluidic power stream from a throat thereof; output receiver channel means for receiving at least a portion of the power stream flow; and a diffuser-type chamber having two opposite divergent side walls effecting a smooth, continuous, and gradual transition from the throat of said input channel means to said output receiver channel means, said chamber defining means for effecting laminar flow of the power stream along both of said side walls to a downstream separation point, control port means communicating with said chamber downstream of said separation point, said chamber thereat effecting an adverse pressure gradient to thereby detach the power stream from one of said side walls whereby the power stream exits into the output receiver channel which is adjacent to the opposite side wall.
 1. A low power side wall separation fluidic logic device with laminar flow characteristics, said device comprising: input channel means for issuing a laminar fluidic power stream from a throat thereof; output receiver channel means for receiving at least a portion of the power stream flow; and a diffuser-type chamber having two opposite divergent side walls effecting a smooth, continuous, and gradual transition from the throat of said input channel means to said output receiver channel means, said chamber defining means for effecting laminar flow of the power stream along both of said side walls to a downstream separation point, control port means communicating with said chamber downstream of said separation point, said chamber thereat effecting an adverse pressure gradient to thereby detach the power stream from one of said side walls whereby the power stream exits into the output receiver channel which is adjacent to the opposite side wall.
 2. A device as defined in claim 1, wherein said control port means are disposed substantially adjacent said output channel means.
 3. A device as defined in claim 1, wherein said throat of said input channel means has a width W, and wherein said side walls of said chamber diverge along a radius of curvature of at least 20W.
 4. A device as defined in claim 1, wherein two output receiver channel means are provided, sAid output receiver channel means diverging from one another at an angle of up to 40* . 